v0.2.1 — watchOS minimum bumped to v8

Fix latent SwiftPM bug: SessionHealthKit/SessionWear depend on synheart-wear-swift which requires watchOS 8.0, but this package declared 6.0. Surfaced when a downstream consumer pulled SessionHealthKit on a real watchOS app.

v0.2.0 — Initial public release

Initial open-source release of the Synheart Session SDK for iOS.

The SDK runs a timer-driven session engine that consumes a
BiosignalProvider (mock, BLE HRM, HealthKit, or your own
implementation) and an optional BehaviorProvider, then emits typed
session events: session_started, biosignal_frame, session_frame,
session_summary, session_error.

Public surface

• SessionEngine with pluggable BiosignalProvider and optional
  BehaviorProvider. MockBiosignalProvider (1 Hz sinusoidal) and
  MockBehaviorProvider ship for local development.
• WearBiosignalProvider — bridges synheart-wear-swift
  BleHrmProvider for real BLE HR streaming.
• HealthKitBiosignalProvider — wraps SynheartWear HealthKit
  streaming via the Combine streamHR() publisher.
• BehaviorSdkProvider — wraps SynheartBehavior.getCurrentStats()
  from synheart-behavior-swift.
• SampleRingBuffer — thread-safe (NSLock) sliding window buffer
  with configurable window.
• HR/HRV computation: mean HR is computed locally; SDNN/RMSSD/pNN50
  are ingested via ingestHsiMetrics() from the upstream runtime.
• SessionError enum with 5 cases (permissionDenied,
  sensorUnavailable, invalidState, lowBattery, osTerminated).

Distribution

• Swift Package Manager — products: SynheartSession,
  SynheartSessionWear, SynheartSessionHealthKit,
  SynheartSessionBehavior.
• CocoaPods — pod 'SynheartSession', '~> 0.2.0'.

Full Changelog: https://github.com/synheart-ai/synheart-session-swift/commits/v0.2.0